Try this link
http://www.investopedia.com/terms/p/price-earningsratio.asp
In simple terms-
A company's (or stock's) worth to a buyer can be judged by how cheap or expensive it is.
PE ratio if high, means more people value the stock more than its earnings. For example, stock price for Bling is 20 and its earning per share is 2, then the PE is 10. This means people are paying less money for the earnings. However, if the price was 40 and the earning per share still 2, then the PE would be 20, meaning people are paying more money for less earnings.
Basically PE gives you the valuation of the stock.